Cushion spring construction



Sept. 3, 1935. E. D. McNALLY CUSHION SPRING CONSTRUCTION Filed Jan. 25,1932 INVENTOR Edward 17. Mnflslly ATTORN EYS Patented Sept. .3, 1935UNITED STATES PATENT. OFFICE CUSHION sramc CONSTRUCTION ApplicationJanuary 25, 1932, Serial No. 588,516

2 Claims.

The present invention pertains to a novel cushion spring construction tobe used in a seat or back or for similar purposes.

The object of the invention is to provide a 5 connector between thehelical springs which is superior in certain respects to theconventional hook or helical connector. The helical connectorsespecially have a tendency to break down, to be pulled loose, or tostretch in service and in handling.

These difiiculties are overcome by the use of a so-called connectingstrip 'in the form of burlap or other suitable fabric placed between therows of coil springs and having close wound helicals sewed into itslongitudinal edges. This member is attached to the top coils of theadjacent coil springs by rings, each of which encircles one of the closewound helicals and the adjacent top coil. The ends of the close woundhelicals are held against slipping or becoming entangled with otherparts by being wound around adjacent border wires.

It has also been found that connecting means of this character iscomparatively noiseless and further provides a smooth top which requirescomparatively less padding than usual.

The invention is fully disclosed by way of example in the followingdescription and in the accompanying drawing, in which- Figure 1 is aplan view constructed according to the invention; and

Fig. 2 is a section on the line 2-2 of Figure 1.

Reference to these views will now be made by use of like characterswhich are employed to des- 3 'ignate corresponding parts throughout.

The drawing illustrates a seat or back cushion spring embodying asuitable or conventional base frame I to which the marginal coil springsmay be attached as will presently be described in detail. The base framemay, for example, be of channel cross section as illustrated in Figure 2to receive the bottom convolutions of the marginal coil springs 2 whichin the present instance are of the hourglass type.

Inner border wires 3 are provided at two opposite edges of the structuredefined by the marginal springs and are secured by means of clips 4 tothe top coils 5 of the springs adjacent which they lie. Each wire has anoutward bend 6 to which is secured a border wire I by clips 8, and theremaining sides of the wire I are secured to the respectively adjacentmarginal coils by similar clips 9. Similar coil springs Ill are mountedwithin the rectangle formed by the marginal springs 2 and have theirbottom coils secured to tional bottom bars ill.

The several coil springs constituting the structure are arranged inparallel rows which may extend either perpendicular or parallel to theborder members 3, and in the present instance are illustrated as lyingperpendicular to these members. For the purpose of interconnecting thecoil springs, strips ll of burlap or other suitable material aredisposed in the spaces between the rows. It will be seen that each suchstrip is doubled back at each longitudinal edge, as at l2 and stitchedto the body of the material as at I3, thereby forming a pocket orenvelope It at each longitudinal edge. In each such pocket is containeda close wound helical spring I5 having its ends l6 extending out of thepocket or envelope, and it will be understood that this unit may beprepared and assembled before being placed in the position illustrated.In making the final assembly, these units are placed in the spacesbetween the rows of springs and are secured to the top coils of theadjacent springs at both sides by means of pairs of small rings I! whichencircle the helicals l5 as well as said coils. The free ends I6 areanchored by being wound around the adjacent border wires 3 so that theycannot slip loose or become entangled with other parts.

As will be seen, the lines of stitching l3 are spaced from the edges ofthe fabric element a distance suflicient to permit rings ll to beinserted through the double plies of the pocket, so that the ringsintersect the pocket. From this it is apparent, that the springs l5 arefree to move relatively to the pocket in the direction of length of thelatter; in fact, prior to the insertion of the rings II, it can bereadily understood that the springs are practically loose within thepocket, the latter having a width largely in excess of the diameter ofthe springs l5. From this it can be understood that the springs l5 aresupported at their ends through the securing of the latter to the borderwire, the fabric portion being supported by the springs, but with thefabric freely movable on the springs, until the rings I! are inserted,these rings serving to prevent shifting of the fabric due to theconnection between the fabric and the springs 2 through the medium ofthe rings, thus leaving the springs l5 freely extensible within thepockets for the meeting of service conditions.

While this may appear to present the condition of contact between thespring l5 and the rings within the pocket, such condition is overcomethrough the fact that the opposing conformations havethe'characteristics of enveloping arcs, with the rings. through thefabric plies, so that the curvature of the ring will tend tocarry thefabric within the space between .the arcs sufliciently to form. abarrieragainst of length of the fabric and the fabric itself wouldcontrol the distance, so that the binding action, which would also beeifective on the springs ll, would prevent expansion of the springsbetween such points-a decrease in distance could be had so far asrespects the fabric, but the closely wound springs it would prevent suchdecrease.

The advantage of this arrangement can be readily understood. Assuming adepression of an area of the seat by an occupant, the top convolutionsof the springs 2 of the area will be lowered, carrying with them theportions of springs it of the area, thus increasing the length of thelatter by extension. The fabric also is carried downward but does notaffect the slight slippage of the springs I! as the latter are extended.'I'hefabric will permit the top convolutions of adjacent springs 2 tomove toward each other but will prevent movement away from one another,due to the presence of the rings and the pocket on opposite sides of thespring It, thus causing'.the fabric to provide a distance-increasinglimitation as between adjacent springs 2; as long as the loweringmovement of the top convolutions of springs 2 does not affect thedistance between convolutions, the lowering action does not affect thenormal relationships of the springs and pockets.

However, this lowering action has an effect on 4 the structures beyondthe lowered area, due to the necessarily increased length of the top ofthe spring structure through its variation from a normally straightline, so that the structure beyond the area presents the limiting effectof .the connection of end springs with the border frame and the limitingeffect of the width of the fabric, so that there is a tendency to resistmovement of the tops of springs 2 in the direction of the lowered areaso far as concerns the direction in which the width of the fabric ispresent. Consequently, the portion of the lowered area taken up by thefabric portion tends to simulate the action of the normal springstructures, with the result that the entire structure takes on thecharacteristics of a spring structure having a larger number of springs2. It will be understood, of course, that the springs Ii aid inproducing this result, since the resistance of these has been added tothe assembly by the lowering action.

The attaching strips provide a reliable and secure interspringconnection and overcome certain of the difficulties experienced withhelical cross connectors, namely breaking down, pulling loose andstretching in, crating and shipping as well as in service. Moreover, theuse of fabric strips eliminates-noise and squeaks in the compression andexpansion of the cushion, and further provides a smooth top whichrequires less padding than is otherwise necessary. Due to thesubstantial area of the fabric strips, the top of the cushion has a feelsimilar to that of a full ,Marshall or bag-enclosed spring construction.

Although a specific embodiment of the invention has been illustrated anddescribed, it will be understood that various alterations in the detailsof construction may be made without departing from the scope of theinvention, as indicated by the appended claims.

What I claim is:

1. In spring seat structures, wherein a plurality of springs arearranged symmetrically to a border frame to provide spaced rows ofsprings with the spacing of material width and substantially uniform inone direction of the structure the combination with the springs andborder frame, of a composite unit spanning the width of the spacebetween such adjacent rows, with the unit positioned in approximatealinement with the top convolutions of the springs, said unit includinga pair of closely-wound helical springs, a fabric member having itslongitudinal edges folded and secured to the body to form side pocxetsto the member and through which the closely wound springs extend andwithin which they are movable extensibly, said member having a width toplace a closely-wound spring and its pocket adjacent the portion of thetop convolutions of springs facing the one side of the space, the endsof the closely-wound springs being secured to opposite points of theborder frame, said unit being secured to the top convolutions of thesprings bordering the space by rings carried by such convolutions andwhich intersect the pocket plies beyond the closely-wound spring tothereby definitely locate the unit relative to the springs of thestructure bordering such space.

2. A structure as in claim 1 characterized in that the securing meansfor completing a pocket is spaced from the pocket edge of the member adistance suflicient to permit passage of a ring intermediate said meansand the closely-wound spring within the pocket, the ring and springpresenting opposing portions of the order of enveloping arcs, andthereby tend to place fabric material within the space between the arcsto substantially eliminate metal to metal contact.

EDWARD D. McNALLY.

